1. Field of the Invention
The present invention relates to an electronic camera, an image processing apparatus, an image processing method and an image processing computer program. More specifically, the invention relates to a technique for recognizing a photographed face image of an object.
2. Description of the Related Art
In electronic cameras, photographed images of objects can be checked on screens such as liquid crystal monitors provided on the rear surfaces of the cameras. As a result, in the case where an object is a person, a facial expression at the time of photographing can be checked.
As a technique for extracting a person's face, for example, Jpn. Pat. Appln. KOKAI Publication No. 8-63597 discloses a method of determining a face candidate region corresponding to a shape of a person's face and determining a face region from the feature quantity in the face candidate region so as to extract the person's face from a color original image.
As a unit that checks face images, for example, Jpn. Pat. Appln. KOKAI Publication No. 2004-240829 discloses a technique for detecting an edge from face portrait image data developed in a memory, extracting a pair of edges as candidates of both eyes, narrowing the candidates according to the feature of the person's face, estimating a face region in the facial portrait image data from the narrowed position of both eyes, obtaining a correcting amount from an average value of luminance in the estimated face region, and correcting the facial portrait image data according to the correcting amount so as to adjust brightness of the facial portrait image data.
Jpn. Pat. Appln. KOKAI Publication No. 6-217187 discloses a technique for adjusting a zoom so that the size of a face portion of an image becomes uniform so as to obtain a stable image even when an object moves.
Jpn. Pat. Appln. KOKAI Publication No. 2003-323615 discloses a technique for accepting a person's face image as a sample image, detecting a region in the vicinity of the face on the image input using a feature of the input sample image, displaying candidates of the detected region in the vicinity of the face on the image, and inputting a narrowing condition for the displayed candidate of the area in the vicinity of the face as to whether the displayed image is a face image so as to execute a face detecting process.
On the other hand, Jpn. Pat. Appln. KOKAI Publication Nos. 5-268513, 9-233384 and 11-84481 disclose techniques for, when a person's face image displayed on a screen is small, enlarging the face image by means of cropping so as to display it on the monitor screen.